1. Field of the Invention
The present invention is directed to a communication method for a magnetic resonance signal from a magnetic resonance reception antenna to an evaluation device, as well as to a reception arrangement for a magnetic resonance signal that is suitable for the implementation of this method, and to a corresponding magnetic resonance system.
2. Description of the Prior Art
Because of the signal-to-noise ratio that can be obtained, it is advantageous in magnetic resonance systems to employ local or surface coils. Such coils are usually connected by a cable to an evaluation device. The cable and the required plug connections, however, represent a limitation on the ease of operation and on the dependability of the surface coil and the corresponding signal transmission.
It is also known to convert a received magnetic resonance signal to a different frequency and to transmit it wirelessly to the evaluation device. Auxiliary energy sources (for example, batteries or accumulators) and radiofrequency oscillators are required for this purpose in the known systems.
For example, German OS 41 26 537 discloses an example of such a system. This published application discloses a communication method for a magnetic resonance signal from a magnetic resonance reception antenna to an evaluation device wherein an auxiliary transmission antenna emits auxiliary energy at an auxiliary frequency, and some of the auxiliary energy is received by an auxiliary reception antenna. The auxiliary signal (or, the received part of the auxiliary signal) is mixed with a magnetic resonance signal received from the magnetic resonance reception antenna to form a mixed signal with a mixed frequency that is equal to the sum of the magnetic resonance frequency and the auxiliary frequency. The mixed signal is broadcast with the mixed frequency by a mixed signal reception antenna.